The present invention is directed to a self-checking system for a frequency detector that is adapted to detect the proximity of a transportation vessel, such as an aircraft transportation vessel, or an intrinsically-safe area.
It may be desirable for certain electronic devices to be deactivated when on board or in proximity to a transportation vessel or in proximity to an intrinsically-safe area. For example, the United States Federal Aviation Administration (FAA) places restrictions on use of certain electronic devices on an aircraft during its operation. These electronic devices may emit electromagnetic fields that could potentially interfere with the aircraft systems, such as its navigation and/or communication systems. Some electronic devices may emit fields during their operation, but do not include transmission communication systems, such as a laptop computer for example. These devices are permitted for use on an aircraft after the aircraft reaches an altitude of ten thousand feet. Other electronic devices that emit fields during communication, such as cellular phones, are not permitted for use on an aircraft at anytime during flight. In addition, the electronic device and/or fields emitted by the electronic devices may cause an unsafe condition if operational in an intrinsically-safe area.
Aircraft do not include automatic detection systems that are capable of detecting when an electronic device having a field-emitting device is being used on the aircraft. Airlines must rely on a flight attendant""s visual inspection to ensure that passengers are not using electronic devices in an improper manner. Therefore, there exists a possibility that a passenger may use a field-emitting electronic device while on-board an aircraft that goes undetected by the flight attendants and that may cause interference with the aircraft systems in an unsafe manner. Electronic devices may also cause undesired interference with other types of transportation vessels, in addition to aircraft, if such electronic devices are not deactivated or disabled.
In addition, many shipping companies attach tracking devices having a field-emitting communication systems (also known as xe2x80x9ctracking devicesxe2x80x9d) to shipping containers to track their geographic location. This allows the shipping company to determine the geographic location of the container as it moves between the origination and destination points to determine whether the goods inside the container are on time, late, or somehow misplaced. For instance, the container may have been misrouted or been placed on the incorrect transportation vessel to reach its destination. The advantages of tracking the position of containers and their associated goods are many and, therefore, such tracking has become commonplace throughout the shipping industry.
A problem occurs when a container having such a tracking device is loaded onto a transportation vessel, such as by ground crew onto an aircraft transportation vessel. The signals emitted by the tracking device may potentially cause interference with the aircraft transportation vessel""s systems. Again, the FAA places restrictions on communication signals, such as those generated by a tracking device, due to their potential interference with flight systems and communications. It may be inadequate to rely on a person to manually switch off the tracking device and/or field-emitting device when entering into the proximity of a transportation vessel or an intrinsically-safe area. For example, human operators and/or ground crew may forget to deactivate the tracking device and/or field-emitting device.
Before the present invention, field-emitting electronic devices, including tracking devices, must be manually deactivated before being loaded onto vessels, such as aircraft transportation vessels, because of this potential interference. To eliminate the possibility of human error, it is necessary that the electronic device and/or tracking device be automatically deactivated so that its signals do not interfere with a transportation vessel while a container associated with the tracking device and/or field-emitting device is proximate to or on board the transportation vessel. The related applications to the present invention, Pending patent application Ser. No. 09/898,498, entitled xe2x80x9cDeactivation of field-emitting electronic device upon detection of a transportation vessel,xe2x80x9d filed on Jul. 3, 2001, which is a continuation-in-part application of Pending patent application Ser. No. 09/542,772, now issued U.S. Pat. No. 6,281,797, entitled xe2x80x9cMethod and apparatus for detecting a container proximate to a transportation vessel hold,xe2x80x9d filed on Apr. 4, 2000, disclose several embodiments that use detection of frequency signals to indicate the proximity of a transportation vessel and thereafter automatically deactivate a field-emitting device and/or a tracking device associated with an electronic device and/or a container. However, a problem may occur if the frequency detector fails to operate properly and detect a transportation vessel due to a malfunction or other error. If the frequency detector fails, the field-emitting device and/or the container will not deactivate its field-emitting and/or tracking device systems, thereby potentially interfering with the transportation vessel systems.
Therefore, a need exists to provide a self-checking feature to determine if a frequency detector that is used to detect the proximity of a transportation vessel is operating properly so that electronic field-emitting and/or tracking devices do not interfere with the transportation vessel""s systems.
The present invention is directed to an electronic field-emitting device that detects the proximity of a transportation vessel and/or intrinsically-safe area. The electronic device may interfere with the transportation vessel systems and/or be unsafe if operational in an intrinsically-safe area. The electronic device, being either a field-emitting device or a tracking device, is capable of deactivating and/or decoupling power from the electronic device and/or its subsystems when the transportation vessel or an intrinsically-safe area is detected so that the field-emitting device does not interfere with the transportation vessel or the intrinsically-safe area. The term xe2x80x9celectronic devicexe2x80x9d is used in this entire summary, description of the invention, and claims to refer to a field-emitting device and/or a tracking device, and use of the term xe2x80x9celectronic devicexe2x80x9d includes a field-emitting device and/or a tracking device.
The electronic device may be any type of electronic device that emits an electrical, magnetic, or electromagnetic field. The field may be generated during communications, or may be generated during the normal operation of the electronic device. One embodiment of an electronic device that generates a field as a result of communication is a cellular phone. Other embodiments of electronic devices that generate a field typically relating to subsystems that do not involve transmission communication include a laptop computer and personal digital assistant (PDA) device. The electronic device contains a frequency detector to determine if the electronic device is proximate to, being loaded into, or is already loaded into a transportation vessel (hereinafter collectively referred to as xe2x80x9cproximatexe2x80x9d or xe2x80x9cin proximity toxe2x80x9d) so that the tracking device can be deactivated so as to not interfere with the communication systems of the transportation vessel.
In another embodiment, the electronic device is a tracking device associated with a container. The tracking device receives information regarding the location of the container, and such location information is communicated remotely for tracking purposes. A frequency detector associated with a container is provided to determine if the container is in proximity to a transportation vessel so that the tracking device can be deactivated so as to not interfere with the communication systems of the transportation vessel.
The transportation vessel may emit particular frequencies that are representative of the operation of the vessel. A frequency detector is coupled to a control system in the electronic device. A frequency generator is coupled to the frequency detector and to the control system as a self-checking device. The control system causes the frequency generator to emit a frequency signal to be picked up by the frequency detector to determine if the frequency detector is operating properly.
In another embodiment, the frequency detector is used to detect frequency signals to signify that an electronic device is in proximity to a transportation vessel. Markers, also called xe2x80x9cfrequency beacons,xe2x80x9d emit specific frequency signals detectable by the frequency detector and are placed in or proximate to the transportation vessel. The frequency detector detects the frequency signals emitted by the frequency beacon(s) that are indicative of the proximity of a transportation vessel, and the frequency signal is passed to the control system for deactivation purposes.
In all embodiments, the control system may periodically cause the frequency generator to emit a frequency signal to check the operation of the frequency detector. The frequency generator is designed to emit substantially the same frequency signal as designed as the representative frequency that is to be detected by the frequency detector. The control system may use a timer that is either polled or that causes an interrupt at the control system. The control system may also check the proper operation of the frequency detector using the frequency generator if a frequency signal is no longer detected by the frequency detector. In this manner, the control system can reactivate the electronic device if the electronic device is not in proximity to the transportation vessel.
The control system can deactivate the system in varying degrees. The control system may include a remote communication device that is used to communicate information from the electronic device to a remote system. The remote communication device can be deactivated so that transmissions are not made while the electronic device is in proximity to a transportation vessel. Other systems may be deactivated in the electronic device based on the frequency signal detected by the frequency detector to conserve power and to further diminish potential interference with the transportation vessel""s systems.